package com.atguigu03.more;

import org.junit.Test;

import java.util.ArrayList;

/**
 * ClassName: Test1
 * Package: com.atguigu03.more
 * Description:
 *
 * @Author BuTang
 * @Create 2023/6/12 10:54
 * @Version 1.0
 */
public class Test1 {
    @Test
    public void test1(){
        ArrayList<? super Father> arrayList = new ArrayList();

        arrayList.add(null);
        arrayList.add(new Father());
        arrayList.add(new Son());
    }

}
class Father{}
class Son extends Father{}
